Trends in Pharmacological, Radioactive Iodine, and Surgical Treatments for Hyperthyroidism in Japan: A Decade-Long Nationwide Claims-Based Analysis (2014-2023).

OBJECTIVE

To investigate the nationwide trends in pharmacological, radioactive iodine (RAI), and surgical treatments for hyperthyroidism in Japan from 2014 to 2023.

METHODS

Annual sex- and age-stratified data on methimazole (MMI), propylthiouracil (PTU), potassium iodide (KI), RAI therapy, and thyroidectomy were extracted from the National Database of Health Insurance Claims (NDB). Crude and age-adjusted counts and rates per 1,000 (drugs) or 100,000 (RAI and surgery) person-years were calculated for each year. The annual trends were analyzed using linear and Poisson regression models.

RESULTS

The cross-sectional distributions strongly reflected the female reproductive life stages. Notably, RAI therapy charges exhibited a bimodal peak distribution in females (25-29 and 45-49 years), whereas thyroidectomy peaked at 30-34 years, coinciding with the intervening childbearing period. Longitudinally, age-adjusted MMI and KI prescriptions and surgeries increased significantly (P ＜0.0001), whereas PTU prescriptions and RAI therapy declined (P ＜0.0001). Subgroup analyses revealed distinct age-dependent shifts, with MMI and KI use increasing across most age groups, particularly among individuals aged ≥90 years. PTU use showed divergent trends by sex, decreasing among males, but increasing among older females, particularly those aged ≥90 years. Surgical interventions increased mainly among older adults, whereas RAI therapy declined across most age groups.

CONCLUSION

Over the past decade, hyperthyroidism management in Japan has shifted toward MMI consolidation, expanded KI use in the super-elderly population, declining RAI therapy in broad-aged populations, and increasing surgery in older adults. These age-dependent treatment shifts reflect the evolving clinical practice and therapeutic challenges posed by a rapidly aging society.